1. Field of the Invention
The present invention relates to the use of proteinaceous materials for use in protection of skin from the generation of sunburn cells in response to ultraviolet radiation.
2. Description of the Prior Art
In recent years, it has become increasingly apparent that cutaneous exposure to solar ultraviolet (UV) radiation mediates a number of harmful effects in the human body. Chronic UV exposure is a well-recognized etiological agent for cutaneous squamous cell and basal cell carcinoma. Elmets Pharmacology of the Skin, Boca Raton, Fla.; CRC Press, 389-416 (1992). Further, UV exposure may play a role in promoting the development of malignant melanomas. Kob KH, et al. "Sunlight and Cutaneous Melanoma: Evidence for and Against Causation," Photochem. Photobiol. 31:765-779 (1990). Histopathologically, acute UV exposure causes solar erythema (sunburn) and is associated with the development of dyskeratotic cells within the epidermis (sunburn cells), a parameter that may reflect UVB-induced DNA damage. Daniels F Jr, et al. "Histochemical Response of Human Skin Following Ultraviolet Irradiation" J. Invest. Dermatol. 37:351-357 (1961); Gilchrest BA, et al. "The Human Sunburn Reaction: Histologic and Biochemical Studies" J. Am. Acad. Dermatol. 5:411-422 (1981).
Recent studies also indicate that UVB radiation can profoundly influence the immune response. Krutmann J, et al. "Recent Studies on Mechanisms in Photoimmunology" Photochem. Photobiol. 48:787-798 (1988). In particular, UV radiation has an inhibitory effect on epidermal Langerhans cells. Gilchrest BA, et al. supra; Tocwa GB, et al. "Epidermal Langerhans Cell Density Determine Whether Contact Sensitivity or Unresponsiveness Follows Skin Painting with DNFB" J. Immunol. 124:445-453 (1980); Rae V, et al. "An Ultraviolet B Radiation Protocol for Complete Depletion of Human Epidermal Langerhans Cells" J. Dermatol. Surg. Oncol. 15:1199-1202 (1989). Langerhans cells represent approximately 2-4% of the entire epidermal population and are essential for the activation and expansion of helper T lymphocytes, an obligatory step in the initiation of immune responses. Kapienberg ML, et al. "Langerhans Cells: A Unique Subpopulation of Antigen Presenting Dendrille Cells" In: Bos, JD, ed. Skin Immune System (SIS), Boca Raton, Fla.; CRC Press, 1990; 109-124. When murine skin is exposed to 200-700 J/m.sup.2 UVB radiation daily for 4 consecutive days, there is a marked reduction in the number of epidermal ATPase-positive Langerhans cells. A reduction in the capacity to initiate cell-mediated immune responses through UV-irradiated skin (Tocwa, GB, et al. supra.) and the induction of suppressor T lymphocytes (Elmets CA, et al. "Analysis of the Mechanism of Unresponsiveness Produced by Haptens Painted on Skin Exposed to Low Dose Ultraviolet Radiation" J. Exp. Med. 158:781-794 (1983)) is also observed. Recent studies indicate that UVB radiation has similar effects in humans. Yoshikawa T, et al. "Susceptibility to Effects of UVB Radiation on Induction of Contact Hypersensitivity as a Risk Factor for Skin Cancer in Humans" J. Invest. Dermatol. 95:530-536 (1990); Cooper KD, et al. "Effect of UV Light on Induction of Immune Response to Epicutaneous Antigen in Humans" FASEB J. 5:A967.
Because humans are exposed to increasing amounts of UV radiation during outdoor recreational activities than in the past (Bowman KP "Global Trends in Total Ozone" Science 239:48-50 (1988); Kripke ML "Impact of Ozone Depletion on Skin Cancers" J. Dermatol. Surg. Oncol. 14:853-857 (1988)), efforts have been made to incorporate sunscreening agents into topical cosmetic products in an attempt to block the adverse clinical, histological and immunological effects of UV radiation exposure on the skin. For example, recent work has indicated that certain extracts from natural products have the ability to reduce the production of sunburn cells and may have an immunostimulating effect on Langerhans cells. E.g., Elmets CA, et al. "Photoprotective Effects of Sunscreens in Cosmetics on Sunburn and Lanngerhans Cell Photodamage" Photodermatol. Photoimmunol. Photomed. 9:113-120 (1992).